1. Field of the Invention
The present invention relates to a tractor such as an agricultural tractor having a steering cylinder for turning the front tires with adjustable steering stops built into the cylinder for controlling the length of stroke of the steering cylinder.
2. Description of Related Art
It is known to equip an agricultural tractor with a hydraulic front steering cylinder that is a double acting cylinder having a piston rod extending in both directions from the cylinder. The rod is coupled to left and right steering knuckles of the tractor by tie rods to turn the front wheels. The extent to which the front wheels can be turned is often controlled by steering stops formed on the steering knuckle and the axle housing. The steering stops may include a boss on the axle and a threaded fastener on the steering knuckle. The fastener head contacts the boss to limit rotation of the knuckle to prevent further turning. The threaded fastener can be turned in or out to adjust the extent of steering travel for different wheel and tire combinations. With the increasing popularity of front suspension axles for agricultural tractors, there is greater competition for space between the tractor chassis and the steering knuckles, making it more difficult to package steering stops at the steering knuckle.
Accordingly, it is an object of the present invention to provide a steering stop that does not interfere with suspension components to thereby provide greater flexibility to the suspension designer for locating the suspension components.
According to the present invention, the steering stops are provided internal to the steering cylinder and thus do not occupy additional packaging space beyond the cylinder itself. The steering cylinder of the present invention has a piston rod extending through and beyond both ends of the cylinder. A piston carried by the rod between the rod and the cylinder transfers the hydraulic force into linear motion of the rod. The rod extends through end caps at each end of the cylinder. The end caps are each threadably mounted to the cylinder and serve as the steering stops. When the piston travels to the point where the piston contacts the stops, travel of the piston is stopped. The stops can be rotated relative to the cylinder to thread the stops in or out, thereby changing the stroke of the steering cylinder.
Once the stops are set to the desired location, they are locked in place by a retainer that is bolted to the cylinder. The retainers can be selectively removed from the cylinder and then used as a wrench to rotate the stops to adjust the cylinder stroke. Adjustment is needed when different wheel and tire combinations are mounted on the tractor or when the tread width is changed. A travel limiter is mounted to the cylinder to prevent complete withdrawal of the stops and the resulting loss of hydraulic oil.